US Patent 11633746 Air treatment apparatus

A docking station for a robotic surface cleaning apparatus has a momentum separator. The momentum separator has an upper wall, a lower wall and a first sidewall extending between the upper and lower walls. The first sidewall comprises a side screen and an end wall is spaced from and faces the side screen whereby an up flow chamber is positioned between the end wall and the side screen. The upper wall also comprises an upper screen and an upper end wall is spaced from and faces the upper screen wherein an upper air flow chamber is positioned between the upper end wall and the upper screen.